Dust prevention in rock drills



Juy 23, 1935. E. M. MITCHELL DUST PREVENTION IN ROCK DRILLS Filed April l1, 1934 Patented July 23, 1935 UNITED STATES DUST PREVENTION IN ROCK DRILLS Ernest Marklow Mitchell, Bexley, New South Wales, Australia Application April 11, 1934, Serial No. 720,106

In Australia 3 Claims.

In theoperation of rock drills, or picks as they are sometimes termed, particularly those of percussion type, a considerable quantity of dust results from the action of the bit on'the rock or the'like, and it is the object of this invention to prevent the dissemination of this dust in dry condition.

It is known to use'water as a dust-laying medium but this practice is ineiective and results in an unnecessary and objectionable sloppiness at the scene of operation. My invention makes use of water in finely atomized form directed on to that part of the surface being operated upon which is adjacent to the bit.

TheV invention is applicable to pneumatically operated drills or picks of single unit hand manipulated type, or of multi-unit type, and it consists in providing means wherebyl the exhaust air is automatically charged with atomized Water in regulated quantity and is directed on to and immediately about the part operated on by the bit to eiiect a dampening or the dust so that it does not readily rise.

According to this invention, there is connected to the exhaust pipe a nozzle which is itself connected to a valved Waterrsupply pipe, said noz-V zle being so constructed and arranged that a fine jet or spray of water is injected into the exhaust pipe in such manner that it is atomized by the rush of exhaust air, the exhaust pipe being extended towards the bit and preferably gradu-l ally increasing in diameter in orderl that the issu-A ing blast is of less velocity than would otherwise be the case, and also that a wider distribution is obtained.

To more fully 'explain the invention reference will now be made to the accompanying drawing which depicts a practical embodiment of the invention and in which Fig. 1 is an elevation of a standard type of. pneumatic percussion drill or pick in operation, and equipped according to this invention;`

Fig. 2 is an elevation to an enlarged scale partly in section showing the nozzle;

Fig. 3 is a sectional plan on line 3-3 of Fig. 2, and f Fig. 4 a sectional elevation on line 4 4 of Fig. 2.

Reference I indicates generally the pneumatic drill or pick coupled to an air supply hose 2, fitted with a bit 3 and having an exhaust pipe 4.

Fitted to Ythe exhaust pipe is an elbow 5, andV to this is coupled a T-piece 6. To one end of the T-piece there is connected an extension l of the exhaust pipe which is of gradually increas- May 30, 19,33

(Cl. Z55-49) ing diameter. Screwed into the stem of the T- piece is the nozzle housing indicated generally by reference 8, and to the outer end of this is attached a regulating tap 9 to which is coupledthe flexible water supply pipe I0.

The nozzle itself consists of a thin metal tube EI flattened at its inner end as at I2 to form a narrow but horizontally lengthy slot I3 through which a iiat jet or spray of water is projected into the T-piece in a direction perpendicular to the 10y flow 'of the exhaust air. The tube I2 is sweated or otherwise secured in a double-ended coupling 8a which at its other end engages a. screwed socket 8b to which the tap 9 is attached..

To minimize the risk of the narrow opening I3 becoming chocked withgrit, a filter screen I4 is tted to the outer end of pipe I I, and if necessary a similar but'slightly coarser screen I5 is iitted to the inner end of tap 9.

It is to be understood that the slot or aperture I3 is of infinitesimal vertical width sothat the injected Water is in eiiect little more than a spray. By means of the tap 9 control of both quantity' and pressure is obtained. i In operation the rush of exhaust air atomizes the injected water, carries it with it and delivers it in a fine spray as shown at I5 (Fig. l) about the bit 3.

I claim:

i. In a pneumatically operated percussion rock drill, means for charging the exhaust air with moisture and directing it on to and about the bit, said means comprising a T-piece on the outer end of` the normal exhaust pipe, an extension of the exhaust pipey of gradually increasing diameter beyond said T-piece and having its open end disposed'to direct the exhaust air on to and about the bit, a water spray nozzle iitted to the ranch of said T-piece and having its outer end krorrned for connection to a water supply pipe, said nozzle having a restricted outlet disposed' to direct into the exhaust pipe a at spray, means for regulating said spray, and Water filtering means at the outer end of said nozzle.

2. In a pneumatically operated percussion drill or pick, means for charging the exhaust air with moisture in atomized condition and for directing it on to and about the bit, said means comprising a water spray nozzle coupled to a pressure water supply pipeand iitted to the air exhaust pipe to inject a spray of water thereinto, a valve on said supply pipe for regulating the quantity of water injected, and a detachable'extension of the exhaust pipe beyond thev water spray nozzle, said extension being of gradually increasing diameter 55 to slow down the velocity of the issuing blast of air and Widen its distribution, the open end of said extension being disposed to direct the moisture-laden air on to the working face about the 5 bit.

charging the exhaust air with moisture in atomzed condition and for directing it on to and about the bit, characterized in that the water spray nozzle is formed to produce a at spray injected perpendicularly to the flow of air in the exhaust pipe.

ERNEST MARKLOW M ITCHELL. 

